Note: Descriptions are shown in the official language in which they were submitted.
CA 02279162 2001-12-18
Patent Application
Attorney Docket No. D/97365
TONER COMPOSITIONS
COPENDING APPLICATIONS
Illustrated in copending applications U.S. Patent No. 6,004,714,
filed concurrently herewith, is a toner comprised of resin, colorant and a
coated
silica, and a coating comprised of an alkylsilane; and U.S. Patent No.
6,214,507,
filed concurrently herewith is a toner with a coated silica with, for example,
certain BET characteristics.
The appropriate components and processes of the copending
applications, such as the alkylsilane coating, may be selected for the present
invention in embodiments thereof.
BACKGROUND OF THE INVENTION
The present invention is generally directed to toner and developer
compositions, and more specifically, the present invention is directed to
positively, or negatively charged toner compositions, or toner particles
containing
coated silica surface additives. The coated silicas are available from
Cabosil, and
more specifically these silicas preferably possess a primary particle size of
about
nanometers to about 55 nanometers and an aggregate size of about 225
nanometers to about 400 nanometers. With the toners of the present invention,
in
embodiments thereof a number of advantages are achievable, such as excellent
25 stable triboelectric charging characteristics, substantial insensitivity to
humidity,
especially humidities of from about 20 to about 80 weight percent, superior
2
CA 02279162 2001-12-18
toner flow through, acceptable triboelectric charging values, such as from
about
15 to about 55 microcoulombs per gram as determined, for example, by the
known Faraday Cage, and wherein the toners enable the generation of
developed images with superior resolution, and excellent color intensity. The
aforementioned toner compositions can contain colorants, such as dyes or
pigments comprised of, for example, carbon black, magnetites, or mixtures
thereof, cyan, magenta, yellow, blue, green, red, or brown components, or
mixtures thereof, thereby providing for the development and generation of
black
and/or colored images, and in embodiments the toner can be selected for two
component development and single component development wherein a carrier or
carrier particles are avoided.
The toner and developer compositions of the present invention can
be selected for electrophotographic, especially xerographic, imaging and
printing
processes, including color, digital processes, and multisystems apparatus and
machines.
PRIOR ART
Toner compositions with certain surface additives, including certain
silicas, are known. Examples of these additives include colloidal silicas,
such as
certain AEROSILS like 8972~ available from Degussa, metal salts and metal
salts of fatty acids inclusive of zinc stearate, aluminum oxides, cerium
oxides,
and mixtures thereof, which additives are each generally present in an amount
of
from about 1 weight percent by weight to about 5 weight percent by weight, and
preferably in an amount of from about 1 weight percent by weight to about 3
weight percent by weight. Several of the aforementioned additives are
illustrated
in U.S. Patents 3,590,000 and 3,900,588.
3
CA 02279162 2001-12-18
Also known are toners containing a mixture of hexamethyldisilazane (HMDZ) and
APTES, an aminopropyltriethoxysilane.
Further, toner compositions with charge enhancing additives, which
impart a positive charge to the toner resin, are also known. Thus, for
example,
there is described in U.S. Patent 3,893,935 the use of quaternary ammonium
salts as charge control agents for electrostatic toner compositions. U.S.
Patent
4,221,856 discloses electrophotographic toners containing resin compatible
quaternary ammonium compounds in which at least two R radicals are
hydrocarbons having from 8 to about 22 carbon atoms, and each other R is a
hydrogen or hydrocarbon radical with from 1 to about 8 carbon atoms, and A is
an anion, for example sulfate, sulfonate, nitrate, borate, chlorate, and the
halogens, such as iodide, chloride and bromide, reference the Abstract of the
Disclosure and column 3; and a similar teaching is presented in U.S. Patent
4,312,933, which is a division of U.S. Patent 4,291,111; and similar teachings
are
presented in U.S. Patent 4,291,112 wherein A is an anion including, for
example,
sulfate, sulfonate, nitrate, borate, chlorate, and the halogens. There are
also
described in U.S. Patent 2,986,521 reversal developer compositions comprised
of toner resin particles coated with certain finely divided colloidal silica.
According
to the disclosure of this patent, the development of electrostatic latent
images on
negatively charged surfaces is accomplished by applying a developer
composition having a positively charged triboelectric relationship with
respect to
the colloidal silica.
Also there is disclosed in U.S. Patent 4,338,390, developer
compositions containing as charge enhancing additives organic sulfate and
sulfonates, which additives can impart a positive charge to the toner
composition.
Further, there is disclosed in U.S. Patent 4,298,672
4
CA 02279162 2001-12-18
positively charged toner compositions with resin particles and pigment
particles,
and as charge enhancing additives alkyl pyridinium compounds. Additionally,
other documents disclosing positively charged toner compositions with charge
control additives include U.S. Patents 3,944,493; 4,007,293; 4,079,014;
4,394,430 and 4,560,635 which illustrates a toner with a distearyl dimethyl
ammonium methyl sulfate charge additive.
Moreover, toner compositions with negative charge enhancing
additives are known, reference for example U.S. Patents 4,411,974 and
4,206,064. The '974 patent discloses negatively charged toner compositions
comprised of resin particles, pigment particles, and as a charge enhancing
additive ortho-halo phenyl carboxylic acids. Similarly, there are disclosed in
the
'064 patent toner compositions with chromium, cobalt, and nickel complexes of
salicylic acid as negative charge enhancing additives.
There is illustrated in U.S. Patent 4,404,271 a toner which contains
a metal complex represented by the formula in column 2, for example, and
wherein ME can be chromium, cobalt or iron. Additionally, other patents
disclosing various metal containing azo dyestuff structures wherein the metal
is
chromium or cobalt include 2,891,939; 2,871,233; 2,891,938; 2,933,489;
4,053,462 and 4,314,937. Also, in U.S. Patent 4,433,040 there are illustrated
toner compositions with chromium and cobalt complexes of azo dyes as negative
charge enhancing additives. These and other charge enhancing additives, such
as these illustrated in U.S. Patents 5,304,449, 4,904,762, and 5,223,368 may
be
selected for the present invention in embodiments thereof.
5
CA 02279162 1999-07-30
SUMMARY OF THE INVENTION
Examples of features of the present invention in embodiments
thereof include:
It is a feature of the present invention to provide toner and
developer compositions with a mixture of certain surface additives, and
wherein the toners possess a number of advantages.
In another feature of the present invention there are provided
negatively charged toner compositions useful for the development of
electrostatic latent images including color images.
to In yet another feature of the present invention there are
provided negatively charged toner compositions useful for the development
of electrostatic latent images including full process color images.
In another feature of the present invention there are provided
toner surface additives that enable fast toner admix as measured by a
~ 5 charge spectrograph.
Also, in another feature of the present invention there are
provided coated silica surface additives that enable toner unimodal charge
distribution as measured by a charge spectrograph.
Further, in another feature of the present invention there are
2o provided certain surface additives that enable an unimodal charge
distribution upon admix of fresh toner into aged toner as measured by a
charge spectrograph.
Other features of the present invention include providing toner
and developer compositions with a mixture of certain surface additives that
25 enable acceptable high stable triboelectric charging characteristics from
for
example about 15 to about 60 microcoulombs per gram, and preferably from
about 25 to about 40 microcoulombs per gram; toner and developer
compositions with coated silica additives that enable humidity insensitivity,
-s-
CA 02279162 1999-07-30
from about, for example, 20 to 80 weight percent relative humidity at
temperatures of from about 60 to about 80°F as determined in a relative
humidity testing chamber; toner and developer compositions with a mixture
of certain surface additives that enable negatively charged toner
compositions with desirable admix properties of 1 second to about 60
seconds as determined by the charge spectrograph, and more preferably
less than about 30 seconds; toner compositions with a mixture of certain
surface additives that enable for example, low temperature fusing resulting
in high quality black and or color images; and the formation of toners with a
~o mixture of coated silica surface additives which will enable the
development
of images in electrophotographic imaging apparatuses, which images have
substantially no background deposits thereon, are substantially smudge
proof or smudge resistant, and therefore are of excellent resolution, and
further, such toner compositions can be selected for high speed
~ 5 electrophotographic apparatuses, that is those exceeding about 60 copies
per minute, and more specifically from about 60 to about 100 copies per
minute.
In another feature of the present invention there are provided
positively charged toner compositions useful for the development of
2o electrostatic latent images including color images.
In yet a further feature of the present invention there are
provided _humidity insensitive, from about, for example, 20 to 80 weight
percent relative humidity at temperatures of from 60 to 80°F as
determined
in a relative humidity testing chamber, positively charged toner compositions
25 with desirable admix properties of about 5 seconds to about 60 seconds as
determined by the charge spectrograph, and preferably less than about 15
seconds for example, and more preferably from about 1 to about 14
CA 02279162 2001-12-18
seconds, and acceptable high stable triboelectric charging characteristics of
from
about 20 to about 50 microcoulombs per gram.
Another feature of the present invention resides in the formation of
toners which will enable the development of images in electrophotographic
imaging apparatuses, which images have substantially no background deposits
thereon, are substantially smudge proof or smudge resistant, and therefore are
of
excellent resolution; and further, such toner compositions can be selected for
high speed electrophotographic apparatuses, that is those exceeding 70 copies
per minute.
According to an aspect of the present invention, there is provided a
process for the preparation of a toner comprising admixing resin, colorant,
and a
coated silica, wherein said silica has a primary particle size of about 25
nanometers to about 55 nanometers and an aggregate size of about 225
nanometers to about 400 nanometers, and said coating is comprised of a mixture
of an alkylsilane and an aminoalkylsilane.
Aspects of the present invention are a toner comprised of resin,
colorant and a coated silica, and wherein said silica has a primary particle
size of
about 25 nanometers to about 55 nanometers and an aggregate size of about
225 nanometers to about 400 nanometers, and said coating is comprised of a
mixture of an alkylsilane and an aminoalkylsilane; a toner wherein said
coating is
generated from a mixture of about 10 weight percent to 25 weight percent of an
alkylalkoxysilane and about 0.10 weight percent to about 5.0 weight percent of
an aminoalkylalkoxysilane; a toner wherein the toner further contains surface
additives of metal oxides, metal salts, metal salts of fatty acids, or
mixtures
thereof; a toner wherein the toner further contains surface additives of
titanic,
metal salts of fatty acids, or mixtures thereof; a toner wherein the resin is
polyester; a toner wherein the resin is a polyester formed by condensation of
propoxylated bisphenol A and a dicarboxylic acid; a toner wherein the resin is
comprised of a mixture of a polyester formed by condensation of propoxylated
bisphenol A and fumaric acid, and a gelled polyester formed by condensation of
propoxylated bisphenol A and fumaric acid; a toner wherein the colorant is
8
CA 02279162 2001-12-18
carbon black, cyan, magenta, yellow, red, orange, green, violet, or mixtures
thereof; a toner wherein the silica is coated with a mixture of a decylsilane
and
8a
CA 02279162 1999-07-30
aminopropylsilane; a toner wherein alkyl contains from about 1 to, about 25
carbon atoms; a toner wherein said alkyl is butyl, hexyl, octyl, decyl,
dodecyl, or stearyl; a toner wherein the silica is coated with a polymer
mixture of (1 ) an alkylsilane, and (2) said aminoalkylsilane; a toner wherein
the titania or titanium dioxide is coated with an alkylsilane; a toner wherein
said titania is coated with decylsilane; a toner wherein the silica is coated
with an input feed mixture of about 10 weight percent to about 25 weight
percent alkyltrialkoxysilane and about 0.10 weight percent to about 5.0
weight percent aminoalkyltrialkoxysilane; a toner wherein alkyl contains from
~ 0 1 to about 25 carbon atoms; a toner wherein the alkyltrialkoxysilane and
the
aminoalkyltrialkoxysilane are coated either in combination or sequentially; a
toner wherein the silica is coated with an input feed mixture of about 5 to
about 15 weight percent decyltrialkoxysilane and about 0.15 weight percent
to about 0.50 weight percent aminoalkyltrialkoxysilane; a toner wherein the
~5 silica has a primary particle size of about 25 nanometers to about 55
nanometers, and the coating is present on a core of silicon dioxide; a toner
wherein the colorant is a pigment, or a dye, and said alkylsilane is an
alkylalkoxysilane; a toner wherein the silica has a primary particle size of
about 30 nanometers to about 40 nanometers; a toner wherein the silica has
2o an aggregate size of about 225 nanometers to about 400 nanometers; or
has an aggregate size of about 300 nanometers to about 375 nanometers,
or has a, primary particle size of about 25 nanometers to about 55
nanometers, or has a primary particle size of about 30 nanometers to about
40 nanometers with an aggregate size of about 150 nanometers to about
25 400 nanometers or an aggregate size of about 200 nanometers to about 275
nanometers; a toner wherein the coated silica is present in an amount of
from about 1 weight percent to about 10 weight percent; a toner wherein the
coated silica is present in an amount of from about 4 weight percent to about
_9_
CA 02279162 1999-07-30
weight percent; a toner wherein the titania is present in an amount from
about 1 weight percent to about 5 weight percent, or wherein the titania is
present in an amount from about 1.5 weight percent to about 3.5 weight
percent; a toner wherein the metal salt is zinc stearate and is present in an
s amount from about 0.10 weight percent to about 0.60 weight percent; a toner
with a triboelectric charge of from about 15 to about 55, or with a
triboelectric
charge of from about 25 to about 40; a toner wherein the resin is present in
an amount of from about 85 weight percent to about 99 weight percent and
the colorant is present in an amount from about 15 weight percent to about 1
~ o weight percent; a developer comprised of toner and carrier; a developer
with
a unimodal charge distribution as measured by a charge spectrograph; a
toner further containing a charge additive, a wax, or mixtures thereof; a
process for the preparation of a toner comprising admixing resin, colorant,
and a coated silica, wherein the silica has a primary particle size of about
25
nanometers to about 55 nanometers and an aggregate size of about 225
nanometers to about 400 nanometers, and the coating is comprised of a
mixture of an alkylsilane and an aminoalkylsilane; a process wherein the
coating mixture is generated from an alkyloxysilane and an
aminoalkylalkoxysilane; a toner wherein the silica coating is a polymer, and
2o said coating is contained on a silicon dioxide core; a toner wherein the
silica
coating is represented by the formula
-.__. a a
'-'~~-S1 x '~'~~-S1~
b c
wherein a represents a repeating segment of the formula
-~ o-
CA 02279162 1999-07-30
a a
'---~0-S1~-~~-S1~
b c
and thereby optionally enables, for example, a crosslinked formula or
structure; the repeating segment above, and hydroxy or hydroxy groups; the
repeating segment above, and alkoxy or alkoxy groups; or the repeating
s segment above, and hydroxy and alkoxy groups; b is alkyl with, for example
from 1 to about 25, and more specifically, from about 5 to about 18 carbon
atoms, and x represents the number of segments and is, for example, a
number of from 1 to about 1,000 and more specifically, from about 25 to
about 500, and wherein c is an aminoalkyl, wherein alkyl contains for
~ o example from about t to about 25 carbon atoms, and wherein c is more
specifically an aminopropyl; a toner wherein said coating is comprised of a
polymer mixture of decylsilane and aminopropylsilane; and toners comprised
of a binder, such as resin particles, colorant, and surface additives
comprised of a mixture of certain silicas, metal oxides, such as titanias,
~ 5 especially titanium dioxides, and certain conductivity aides such as metal
salts of fatty acids, such as zinc stearate; and toner compositions comprised
of binder, colorant, optional additives such as charge additives, optional
surface additives such as certain titanias and conductivity aides such as zinc
stearate, and a surface additive comprised of silica coated with a mixture of
2o an alkylsilane, such as decylsilane and aminopropylsilane, each present in
the mixture as a coating on the silica in various suitable amounts. Based on
the weight of silica, the feed input for the alkylsilane such as decylsilane
is,
for example, from about 5 weight percent to 25, and preferably, for example.
CA 02279162 1999-07-30
from about 10 to about 20 weight percent, and the feed input for the
aminoalkylsilane, such as aminopropylsilane is for example from about 0.05
weight percent to 5.0, or from about 0.05 to about 3 weight percent. For
example, 100 grams of silica can be mixed with 15 grams of
decyltrimethoxysilane and 0.50 grams of aminopropyltriethoxysilane, either
together or sequentially. The resulting silica can then be reacted with the
decyltrimethoxysilane and aminopropyltriethoxysilane to form a coating on
the silica surface. These coated silica particles can be blended on the toner
surface in an amount of for example, from about 0.50 weight percent to 10
~ o weight percent, and preferably from about 2.0 weight percent to about 5.0
weight percent. The toner may also include optional additional known
surface additives such as certain uncoated or coated metal oxides, such as
titania particles present for example in various suitable amounts, like from
about 0.50 weight percent to about 10 weight percent, and preferably from
about 1.5 weight percent to about 4 weight percent of titania which has been
coated with a feed input of from about 5 weight percent to about 15 weight
percent decyltriethoxysilane or decyltrialkoxysilane. In addition, the toner
may also include further optional surface additives such as a conductivity
aides such as metal salts of fatty acids, like zinc stearate in an amount of,
2o for example, from about 0.05 weight percent to about 0.60 weight percent.
The coated silica and optional titania surface additives each preferably
poss~,S._a primary particle size of from about 20 nanometers to about 400
nanometers and preferably from about 25 nanometers to about 55
nanometers.
The coating can be generated from an alkylalkoxy silane and
an aminoalkyloxy silane as illustrated herein, and more specifically, from a
reaction mixture of a silica like silicon dioxide core and an alkylalkoxy
silane,
such as decyltrimethoxy silane, and an aminoalkyloxy silane, such as
~12-
CA 02279162 1999-07-30
aminopropylalkoxy silane. There results from the reaction mixture the
coating contained on the silica core, and optionally containing residual
alkoxy groups, and/or hydroxy groups. Preferably, in embodiments the
coating is a mixture of the alkylsilane and aminoalkyl silane polymeric
s coating that contains crosslinking and which coating may, it is believed, be
represented by the formula
a a
---~O-Sid----f0-Si~--
b c
wherein a represents a repeating segment shown above, and more
specifically, a is, for example,
a a
--~O-Si X O-Si~-
b c
,o
thereh~optionally enabling, for example, a crosslinked formula or structure;
a repeating segment above, and hydroxy or hydroxy groups; a repeating
segment, and alkoxy or alkoxy groups; or a repeating segment, and hydroxy
and alkoxy groups; b is alkyl with, for example from 1 to about 25, and more
~ s specifically, from about 5 to about 18 carbon atoms; and x represents the
number of segments and is, for example, a number of from 1 to about 1,000
and more specifically from about 25 to about 500, and wherein c is
-13-
CA 02279162 2001-12-18
preferably an aminoalkyl, wherein alkyl contains, for example, from about 1 to
about 25 carbon atoms, and wherein c is, more specifically, an aminopropyl,
and
b is decyl. The titanium dioxide surface additive can be of a similar formula
or
structure illustrated with regard to the alkylsilane except that the Si is
replaced
with Ti.
The toner compositions of the present invention can be prepared
by admixing and heating resin particles such as styrene polymers, polyesters,
and similar thermoplastic resins, colorant wax, especially low molecular
weight
waxes, and charge enhancing additives, or mixtures of charge additives in a
toner extrusion device, such as the ZSK53T"" available from Werner Pfleiderer,
and removing the formed toner composition from the device. Subsequent to
cooling, the toner composition is subjected to grinding utilizing, for
example, a
Sturtevant micronizer for the purpose of achieving toner particles with a
volume
median diameter of less than about 25 microns, and preferably of from about 8
to
about 12 microns, which diameters are determined by a Coulter Counter.
Subsequently, the toner compositions can be classified utilizing, for example,
a
Donaldson Model B classifier for the purpose of removing fines, that is toner
particles less than about 4 microns volume median diameter. Thereafter, the
coated silica and other additives are added by the blending thereof with the
toner
obtained.
Illustrative examples of suitable toner binders, include toner resins,
especially polyesters, thermoplastic resins, polyolefins, styrene acrylates,
such
as PSB-2700T"" obtained from Hercules-Sanyo Inc., and preferably selected in
the amount of about 57 weight percent, styrene methacrylate, styrene
butadienes, crosslinked styrene polymers, epoxies, polyurethanes, vinyl
resins,
including homopolymers or copolymers of two or more vinyl monomers; and
polymeric esterification products of a dicarboxylic acid and a diol comprising
a
diphenol. Vinyl monomers include styrene,
14
CA 02279162 2001-12-18
p-chlorostyrene, unsaturated mono-olefins such as ethylene, propylene,
butylene, isobutylene and the like; saturated mono-olefins such as vinyl
acetate,
vinyl propionate, and vinyl butyrate; vinyl esters like esters of
monocarboxylic
acids including methyl acrylate, ethyl acrylate, n- butylacrylate, isobutyl
acrylate,
dodecyl acrylate, n-octyl acrylate, phenyl acrylate, methyl methacrylate,
ethyl
methacrylate, and butyl methacrylate; acrylonitrile, methacrylonitrile,
acrylamide;
mixtures thereof; and the like, styrene butadiene copolymers with a styrene
content of from about 70 to about 95 weight percent, reference the U.S.
patents
mentioned herein, the disclosures of which have been totally incorporated
herein
by reference. In addition, crosslinked resins, including polymers, copolymers,
homopolymers of the aforementioned styrene polymers, may be selected.
As one toner resin, there are selected the esterification products of
a dicarboxylic acid and a diol comprising a diphenol. These resins are
illustrated
in U.S. Patent 3,590,000. Other specific toner resins include
styrene/methacrylate copolymers, and styrene/butadiene copolymers; Pliolites;
suspension polymerized styrene butadienes, reference U.S. Patent 4,558,108
polyester resins obtained from the reaction of bisphenol A and propylene
oxide;
followed by the reaction of the resulting product with fumaric acid, and
branched
polyester resins resulting from the reaction of dimethylterephthalate, 1,3-
butanediol, 1,2-propanediol, and pentaerythritol, reactive extruded resin,
especially reactive extruded polyesters with crosslinking as illustrated in
U.S.
Patent 5,352,556 styrene acrylates, and mixtures thereof. Also, waxes with a
molecular weight MW weight average molecular weight of from about 1,000 to
about 20,000, such as polyethylene,
CA 02279162 1999-07-30
polypropylene, and paraffin waxes, can be included in, or on the toner
compositions as fuser roll release agents. The resin is present in a
sufficient, but effective amount, for example from about 50 to about 90
weight percent.
Colorant includes pigment, dyes, mixtures thereof, mixtures of
dyes, mixtures of pigments and the like present in suitable amounts such as
from about 1 to about 20 and preferably from about 2 to about 10 weight
percent. Colorant examples are carbon black like REGAL 330~; magnetites,
such as Mobay magnetites M08029TM, M08060TM; Columbian magnetites;
~o MAPICO BLACKSTM and surface treated magnetites; Pfizer magnetites
CB4799TM, C85300TM, CB5600TM, MCX6369TM; Bayer magnetites,
BAYFERROX 8600TM, 8610TM; Northern Pigments magnetites, NP-604TM,
NP-608TM; Magnox magnetites TMB-100TH', or TMB-104TM; and the like;
cyan, magenta, yellow, red, green, brown, blue or mixtures thereof, such as
~5 specific phthalocyanine HELIOGEN BLUE L6900TM, D6840TM, D7080TM,
D7020TM, PYLAM OIL BLUET'", PYLAM OIL YELLOWTM, PIGMENT BLUE
1TM available from Paul Uhlich & Company, Inc., PIGMENT VIOLET 1TM,
PIGMENT RED 48TM, LEMON CHROME YELLOW DCC 1026TM, E.D.
TOLUIDINE REDTM and BON RED CTM available from Dominion Color
2o Corporation, Ltd., Toronto, Ontario, NOVAPERM YELLOW FGLTM,
HOSIAP-ERM PINK E''~' from Hoechst, and CINQUASIA MAGENTATM
available from E.I. DuPont de Nemours & Company, and the like. Generally,
colored pigments and dyes that can be selected are cyan, magenta, or
yellow pigments or dyes, and mixtures thereof. Examples of magentas that
25 may be selected include, for example, 2,9-dimethyl-substituted quinacridone
and anthraquinone dye identified in the Color Index as CI 60710, CI
Dispersed Red 15, diazo dye identified in the Color Index as CI 26050, CI
-1 &
CA 02279162 2001-12-18
Solvent Red 19, and the like. Illustrative examples of cyans that may be
selected
include copper tetra(octadecyl sulfonamido) phthalocyanine, x-copper
phthalocyanine pigment listed in the Color Index as CI 74160, CI Pigment Blue,
and Anthrathrene Blue, identified in the Color Index as CI 69810, Special Blue
X-
2137, and the like; while illustrative examples of yellows that may be
selected are
diarylide yellow 3,3-dichlorobenzidene acetoacetanilides, a monoazo pigment
identified in the Color Index as CI 12700, CI Solvent Yellow 16, a nitrophenyl
amine sulfonamide identified in the Color Index as Foron Yellow SE/GLN, CI
Dispersed Yellow 33 2, 5-dimethoxy-4-sulfonanilide phenylazo-4'-chloro-2, 5-
dimethoxy acetoacetanilide, and Permanent Yellow FGL, and known suitable
dyes, such as red, blue, green, and the like.
Magnetites include a mixture of iron oxides (FeO.Fe203), including
those commercially available as MAPICO BLACKT"", and are present in the toner
composition in various effective amounts, such as an amount of from about 10
weight percent by weight to about 75 weight percent by weight, and preferably
in
an amount of from about 30 weight percent by weight to about 55 weight percent
by weight.
There can be included in the toner compositions of the present
invention charge additives as indicated herein in various effective amounts,
such
as from about 1 to about 19, and preferably from about 1 to about 3 weight
percent, and waxes, such as polypropylenes and polyethylenes commercially
available from Allied Chemical and Petrolite Corporation, Epolene N-15T""
commercially available from Eastman Chemical Products, Inc., Viscol 550-P TM,
a
low weight average molecular weight polypropylene available from Sanyo Kasei
K.K., and the like. The commercially available polyethylenes selected have a
molecular weight of from about 1,000 to about 1,500, while the commercially
available polypropylenes utilized are
17
CA 02279162 2001-12-18
believed to have a molecular weight of from about 4,000 to about 7,000. Many
of
the polyethylene and polypropylene compositions useful in the present
invention
are illustrated in British Patent No. 1,442,835. The wax is present in the
toner
composition of the present invention in various amounts, however, generally
these waxes are present in the toner composition in an amount of from about 1
weight percent by weight to about 15 weight percent by weight, and preferably
in
an amount of from about 2 weight percent by weight to about 10 weight percent
by weight. The toners of the present invention may also in embodiments thereof
contain polymeric alcohols, such as UNILINS°, reference U.S. Patent
4,883,736
and which UNILINS~ are available from Petrolite Corporation.
Developers include the toners illustrated herein with the mixture of
silicas on the surface and carrier particles. Developer compositions can be
prepared by mixing the toners with known carrier particles, including coated
carriers, such as steel, ferrites, and the like, reference U.S. Patents
4,937,166
and 4,935,326 for example from about 2 weight percent toner concentration to
about 8 weight percent toner concentration. The carriers can include coatings
thereon, such as those illustrated in the 4,937,166 and 4,935,326 patents, and
other known coatings. There can be selected a single coating polymer, or a
mixture of polymers. Additionally, the polymer coating, or coatings may
contain
conductive components therein, such as carbon black in an amount, for example,
of from about 10 to about 70 weight percent, and preferably from about 20 to
about 50 weight percent. Specific examples of coatings are fluorocarbon
polymers, acrylate polymers, methacrylate polymers, silicone polymers, and the
like.
18
CA 02279162 2001-12-18
Imaging methods are also envisioned with the toners of the present
invention, reference for example a number of the patents mentioned herein, and
U.S. Patents 4,585,884; 4,584,253; 4,563,408 and 4,265,990.
The following Examples are being submitted to further define
various pieces of the present invention. These Examples are intended to be
illustrative only and are not intended to limit the scope of the present
invention.
Comparative Examples and data are also submitted.
EXAMPLE I
Preparation of Coated Silica
200 Milliliters of dry n-propanol solvent were placed in a three neck
500 milliliters round bottom flask, and the solvent was sparged with dry
nitrogen
to remove excess oxygen. One 10 milliliter aliquot of solvent was removed to a
small 2 dram vial and set aside. A second 20 milliliter aliquot was also
removed
and placed in a scintillation vial. 15 Grams of untreated hydrophilic Si02
silica
TL90T"" available from Cab-O-Sil Corp. with a primary particle size of 30
nanometers as measured by BET, named for Brunauer, Emmett, and Teller, and
which BET is a standard known technical method that measures surface area,
and with model assumptions there can be calculated, for example, the primary
particle size, and an aggregate size of about 300 nanometers as measured by
Browning Motion was added to the flask and mixed with a mechanical mixer until
wetted. An inert atmosphere was maintained during this mixing. A few drops of
diethylamine was added to the 10 milliliter aliquot of solvent and the
resulting
mixture was added to the 500 milliliter flask. The mixture was then stirred
for
approximately 1 hour. To the 20 milliliters of solvent in the scintillation
vial were
added 2.25 grams of decyltrimethoxysilane and 0.06 gram of
aminopropyltriethoxysilane. This mixture was added to the 500 milliliter flask
containing the Si02 after
19
CA 02279162 1999-07-30
the 1 hour of the above pretreatment was completed. A heating mantle was
attached, and the mixture was heated to reflux with stirring and under the
inert atmosphere. Heat was applied for approximately 5 hours and then was
turned off and the mixture was allowed to cool down to room temperature,
about 25°C. The mixture then was transferred to a tear shaped flask and
the
flask attached to a rotovapor evaporator and the solvent stripped off with
heat and vacuum. The flask was transferred to a vacuum oven and the
drying completed over night, about 18 hours throughout under full vacuum
and moderate temperature of 40°C. The resulting
~o decylsilane/aminopropylsilane coated silica was crushed with a mortar and
pestle, and had a primary particle size of 30 manometers as measured by
BET and an aggregate size of about 300 manometers as measured by
Browning Motion.
EXAMPLE II
Preparation of Coated Silica
Thirty grams of an untreated hydrophilic Si02 silica powder
core with a primary particle size of 40 manometers and an aggregate size of
about 300 manometers were placed in a Buechi 2 liter autoclave reactor, and
2o the reactor was sealed. An inert gas, argon, was then purged for 30 minutes
through the reactor to remove atmospheric gases. The reactor was then
evacuated of atmospheric gases using a vacuum pump and warmed to 28°C.
The vacuum valve was then closed and an ampoule of triethylamine was
connected to the reactor such that the vapor space of the ampoule and the
25 upper portion of the reactor are connected, thereby allowing the vapor
phase
transport of triethylamine to the bed of silica for 15 minutes. The valve from
the ampoule to the reactor was then closed and the valve to the vacuum
reopened to remove the triethylamine that was not physisorbed to the
-2o-
CA 02279162 1999-07-30
surface of silica. The reactor was then cooled to 0°C with the aide of
a
Laude circulating bath connected to the reactor jacket. After achieving a
temperature of 0°C, 570 grams of carbon dioxide (bone-dry grade
obtained
from Praxair) were then added to the chilled reactor with the assistance of
s an ISCO Model 260D motorized syringe pump. Agitation of the reactor was
then initiated at 10 rpm. 4.5 Grams of decyltrimethoxysilane from Shin-Etsu
Silicones, and 0.12 gram of aminopropyltrimethoxysilane from PCR
Research Chemicals catalog were then dissolved in separate variable
volume pressure cells using carbon dioxide as the solvent. The pressure in
1o the cell was 100 bar which was sufficient to generate a homogeneous
solution of the two silanes in carbon dioxide. The decyltrimethoxysilane
solution was then injected into the Buechi 2 liter reactor. This injection
procedure was then repeated with the 0.12 gram of
aminopropyltriethoxysilane. Subsequent to the injection of this second
15 reagent, the temperature of the reactor was maintained at 0°C and
agitated
at 100 rpm for 30 minutes; the agitation was then stopped, and the carbon
dioxide was vented off from the upper portion of the reactor, the vapor
space. Subsequent to the aforementioned depressurization, the reactor
temperature was increased to 28 to 30°C. After equilibration at this
2o temperature, the resulting decylsilane/aminopropylsilane treated or coated
silica product was removed for overnight vacuum treatment (about 18 hours,
150°C for ,three hours) and then spectroscopically characterized via
infrared
spectroscopy.
-21-
CA 02279162 2001-12-18
EXAMPLE III
A toner resin was prepared by a polycondensation reaction of
bisphenol A and fumaric acid to form a linear polyester referred to as Resapol
HT.
A second polyester was prepared by selecting Resapol HT and
adding to it in an extruder a sufficient amount of benzoyl peroxide to form a
crosslinked polyester with a high gel concentration of about 30 weight percent
gel, reference U.S. Patents 5,376,494; 5,395,723; 5,401,602; 5,352,556, and
5,227,460, and more specifically, the polyester of the '494 patent.
EXAMPLE IV
75 Parts by weight of the resin Resapol HTTM from Example III,
14 parts by weight of the 30 weight percent gel polyester from Example III,
and,
11.0 parts by weight of Sun Blue Flush, which is a mixture of 30 weight
percent
P.B.15:3 copper phthalocyanine and 70 weight percent Resapol HT prepared at
Sun Chemicals by flushing to obtain a high quality pigment dispersion, were
blended together and extruded in a ZSK-40 T"" extruder. The extruded blend was
then jetted and classified to form a cyan toner (with 93 weight percent of
resin
and about 7 weight percent of P.B.15:3) with a toner particle size of about
6.5
microns as measured by a Layson Cell. The final cyan toner had a gel
concentration of 5 weight percent.
COMPARATIVE EXAMPLE V
A thirty gram sample of toner from Example IV was added to a 9
ounce jar with 150 grams of stainless steel beads. To this was added 0.6
weight
percent TS530 TM (15 nanometers of primary particle size fumed silica
22
CA 02279162 2001-12-18
coated with hexamethyldisilazane from Cab-O-Sil Division of Cabot Corp.), 0.9
weight percent TD3103TM (15 nanometers of primary particle size titanium
dioxide coated with decylsilane generated from decyltrimethoxysilane from
Tayca
Corp.), and 0.3 weight percent zinc stearate L from Synthetic Products
Company.
After mixing on a roll mill for 30 minutes, the steel beads were removed from
the
jar.
A developer was prepared by mixing 4 parts of the blended toner
with 100 parts of a carrier of a Hoeganaes steel core coated with 80 weight
percent of polymethylmethacrylate and 20 weight percent of a conductive carbon
black. Testing of this developer in an imaging fixture similar to the Xerox
5090T""
resulted in poor image quality primarily because of a loss in developability
of the
toner caused by, for example, the small size 15 nanometer TS530TM silica,
small
size 15 nanometers of the TD3103TM titanium dioxide, and/or coatings on the
silica.
COMPARATIVE EXAMPLE VI
A toner blend was prepared as in Example V except 4.2 weight
percent RX515HT"" (40 nanometers of primary particle size and about 300
nanometers of aggregate size fumed silica coated with a mixture of
hexamethyldisilazane and aminopropyltriethoxysilane, which coated silica was
obtained from Nippon Aerosil Corp.), 2.5 weight percent of MT5103T"" (30
nanometers of primary particle size titanium dioxide coated with decylsilane
obtained from Tayca Corp.), and 0.3 weight percent zinc stearate L from
Synthetic Products Company, were blended onto the toner surface. After mixing
on a roll mill for 30 minutes, the steel beads were removed from the jar. A
developer was prepared by mixing 4 parts of the above blended toner with 100
parts of a carrier of Hoeganaes steel core coated with polymethylmethacrylate
and 20 weight percent of a conductive carbon black.
23
CA 02279162 1999-07-30
A 90 minute paint shake time track was completed for this developer with a
resulting toner tribo at the end of 90 minutes equal to -16.5
microcoulombs/gram. During the 90 minute time track, tribo was unstable
and decreased with increasing time. An admix evolution was accomplished
s at the end of the 90 minutes resulting in a unimodal charge distribution at
15
seconds, but becoming bimodal by 1 to 2 minutes of additional paint
shaking. This bimodal distribution consisted of incumbent toner that had
moved toward zero charge, and incoming toner that charged against the
incumbent toner to a higher charge level than incumbent toner. Upon
~ o breadboard machine, similar to the Xerox Corporation 5090 testing with
freshly blended toner from above, low quality images resulted after about
2,000 copies were made. The poor images were caused primarily by wrong
sign toner, the bimodal charge distribution that occured in the machine
developer housing, which was simulated by the paint shake time
~ 5 track/admix. The low q/d charge toner with a q/d near zero resulted in
dirt
and background on the image and the high q/d charge toner with a q/d (fc/u
femtocoulombs per micron) of about 0.7 or greater adhered to the developer
wires resulting in poor development as evidenced by low image density in
parts of the image.
EXAMPLE VII
A toner blend was generated as in Example VI except the
RX515H was replaced with 3.2 weight percent of a 30 nanometer primary
particle size and about 300 nanometer aggregate size fumed silica core (L90
2s core) coated with a feed mixture of 15 weight percent decyltrimethoxysilane
and 0.4 weight percent aminopropyltriethoxysilane, which coated silica was
obtained from Cab-O-Sil division of Cabot Corp.
-24-
CA 02279162 1999-07-30
A developer was prepared by mixing 4 parts of the above
blended toner with 100 parts of a carrier of a Hoeganaes steel core coated
with 80 weight percent polymethylmethacrylate and 20 weight percent of a
Vulcan conductive carbon black. A 90 minute paint shake time track was
completed for this developer with a resulting toner tribo at the end of 90
minutes equal to -19.7 microcoulombs/gram. During the 90 minute time
track, toner tribo was stable and did not decrease with increasing time.
Admix was accomplished at the end of the 90 minutes, resulting in a
unimodal charge distribution at 15 seconds. Unlike the developer in
t o Example VI, the charge distribution of the incumbent and incoming toner in
this Example remained unimodal with no low charge (<0.2 fc/u) or wrong
sign toner with a q/d (femtocoulombs/micron, q being the toner charge and d
being toner diameter) near zero or less than zero throughout the additional 2
minutes of total paint shaking. This developer enabled excellent copy
~ s quality images having excellent image density and low acceptable
background.
EXAMPLE VIII
A toner blend was prepared as in Example VI except the
2o RX515H was replaced with 3.2 weight percent of a 30 manometer primary
particle size and about 300 manometer aggregate size fumed silica core (L90
core) coated with a feed of 15 weight percent decyltrimethoxysilane and 0.5
weight percent aminopropyltriethoxysilane, which coated silica containing
decylsilane and aminopropylsilane was obtained from Cab-O-Sil division of
25 Cabot Corp. A developer was prepared by mixing 4 parts of the above
blended toner with 100 parts of a carrier of Hoeganaes steel core coated
with 80 weight percent polymethylmethacrylate and 20 weight percent of a
conductive carbon black. A 90 minute paint shake time track was completed
-25-
CA 02279162 1999-07-30
for this developer with a resulting toner tribo at the end of 90 minutes equal
to -18.9 microcoulombs/gram. During the 90 minute time track, toner tribo
was stable and did not decrease with increasing time. Admix was
accomplished at the end of the 90 minutes, resulting in a unimodal charge
s distribution at 15 seconds. Unlike the developer in Example VI, the charge
distribution of the incumbent and incoming toner in this Example remained
unimodal with no low charge (< 0.2 fc/u) or wrong sign positively charged
toner having a q/d near zero or less than zero throughout the 2 minutes of
additional paint shaking. This developer enabled excellent copy quality
~o images having excellent image density and low/acceptable background in a
Xerox Corporation 5090 breadboard test fixture.
Other modifications of the present invention may occur to one
of ordinary skill in the art subsequent to a review of the present
application,
and these modifications, including equivalents thereof, are intended to be
15 included within the scope of the present invention.
~26-
